The present invention relates generally to the field of transaction processing, and more specifically to processing multiple callout messages in a transaction processing system.
A transaction processing system (TPS) receives a request from a client system (such as an online transaction program (OTP)), sends the request to a server system where the server performs operations in accordance with the request. If the request calls for a response, the server sends a return message and/or data to the requesting client system.
A callout is a request that can be initiated by an online transaction program (OTP) at any time during an application program flow. The OTP directs the callout request to an external program (for example, to retrieve needed information, or to cause the external program to perform some operations). For example, a checking account program (which is an OTP) in a commercial bank computer system issues a callout request to a database server, to obtain certain customer information. The database server returns the requested customer information and the checking account program can then continue processing.